(1) Field of the Invention
This invention relates to shoe sole molding, and more particularly to the manufacture of shoe soles by the injection of a settable fluid material into a cavity of a unique sole mold having a retractable form mechanism therewithin.
(2) Prior Art
Unit soles comprised of injectable plastic-like material have come on the market to compete with inexpensively manufactured shoes from foreign countries. These unit soles are utilized on all types of footwear, from boots, to shoes, to sandals. In the manufacture of unit soles for sandals, a method was needed to secure the straps which may comprise the upper, to the sole, in a manner which is cost effective, comfortable to the wearer, and which provides a long service life.
Sewing the straps to the sole liner may fit several of these requirements, but that method may also be uncomfortable to the user and may not hold together for several seasons of wear.
Footwear manufacturers subsequently tried manual drilling of the sole material to fabricate the holes at a slight angle to the bottom of the soles, that is, through the side wall of the sole and out the top surface of the sole near the edge thereof, to provide a hole or channel by which the straps or upper may be secured to the sole. This method of making the holes or channels in the soles is a time consuming, error-prone activity.
It is an object of the present invention to obviate the problems associated with the prior art attempts at manufacturing unit soles, especially unit soles for sandals.
It is a further object of the present invention, to eliminate one of the time consuming hand operations of the footwear manufacturer.
It is yet a further object of the present invention, to provide an apparatus for producing the desired holes or channels in the unit soles while they are still in the mold cavity and which apparatus may be retracted from the molded sole to allow the sole to be easily removed from the mold cavity, particularly since the channel forming mechanism might be obtuse with or otherwise get in the way of direct removal of the molded sole from the cavity.